The present invention relates to an image forming apparatus provided with a conductive fur brush for brushing the surface of a sensitive body.
In the case of conventional electrophotographic copying machines, a toner image is formed on a sensitive body in accordance with well known electrophotographic processes and this image is transferred to a sheet of transfer paper. However, the toner image which is on the sensitive body is not 100% transferred to the transferring paper. Instead, toner in an amount which usually ranges between 20% and 40% is not transferred but is instead left on the sensitive body. When this happens, the toner which remains on the sensitive body after the transfer process must be removed so as not to influence the next such process; and a cleaning device is used to achieve this purpose.
One type of cleaning device which is well known is a fur brush type of cleaner which comprises a rotating conductive fur brush to which a bias voltage has been applied. This brush is then used to brush the surface of the sensitive body to remove any toner remaining on it. However, such a fur brush is continuously subjected to rapid bending stress; so that when it is used for a long period, some of the fur falls off and is broken, and these fur pieces are carried to the downstream side of the machine, following the rotation of the sensitive body and resulting in a variety of problems. The fur may stick to the discharger wire and result in abnormal discharge, or may enter the developer to partially break an image, or may adhere to a sheet of transfer paper to make a copy unacceptable; further, the fur may adhere to the heat roller of the fixer located on the downstream side of the machine and result in contamination of the fixer. Because of the structure of such photocopying machines, it is difficult to prevent the fur from falling and breaking off. This necessitates a member which will prevent the separated fur from being carried throughout and scattered within the machine. Conventional fur brush cleaning devices generally employ a Mylar film or similar material to prevent toner from being scattered, but this is the only purpose it can serve. However stongly the Mylar film may come into contact with the sensitive body, it is not possible for it to shield the broken and separated furs; instead these furs damage the sensitive body to a greater degree. Thus, the fallen or broken furs cannot be prevented from scattering through the machine.